0002434: merge sketches produces sketch on XY plane when original sketches were on XZ

Description

merging two sketches on the XZ plane will produce a sketch on the XY plane.

Steps To Reproduce

create two new sketches, each time selecting the XZ plane in the creation dialogue, enter some simple geometry, use Sketcher "merge sketches", then result will correctly merge the elements within the sketch but mount the new merged sketch to the (default) XY plane.

Activities

in a simple example where all the sketches are on the same plane the solution seems logical, the output merged sketch could logically be expected to be also placed on the same plane.

However when sketches mounted on different planes are merged, then desired output could be less certain.

Perhaps a solution could be to invoke a plane selection dialogue similar to that which pops up when you select "create new sketch" with nothing selected, and use that to select the desired output sketch plane?

I have added a simple example file with four sketches, one each on each plane containing a 1, 2 or 3 and the result of 'merge sketches' which is on the xy plane.